JP7571726B2 - Image sensor and image pickup device - Google Patents

Description

The present disclosure relates to an imaging element using an organic material and an imaging device equipped with the same.

For example, Patent Document 1 discloses a photoelectric conversion element having an organic layer containing a compound represented by the following general formula (3): R7 in the compound represented by general formula (3) is an aryl group, a heteroaryl group, or an alkenyl group.

International Publication No. 2015/119039

However, there is a demand for improved external quantum efficiency in imaging elements that use organic materials.

It is desirable to provide an imaging element and an imaging device that can improve external quantum efficiency.

An imaging element according to an embodiment of the present disclosure includes a first electrode, a second electrode disposed opposite to the first electrode, and an organic layer provided between the first electrode and the second electrode and containing at least one dipyrromethene derivative represented by any of formulas (1-1) to (1-24) and formulas (2-1) to (2-6) described below .

An imaging device according to one embodiment of the present disclosure includes a plurality of pixels, each of which is provided with one or more organic photoelectric conversion units, and has the imaging element according to the above embodiment as the organic photoelectric conversion unit.

In the photoelectric conversion element of the embodiment and the imaging device of the embodiment of the present disclosure, at least one dipyrromethene derivative represented by any one of formulas (1-1) to (1-24) and formulas (2-1) to (2-6) is used to form an organic layer, thereby improving the absorption efficiency of light in a predetermined wavelength band (specifically, blue light).

1 is a schematic cross-sectional view illustrating an example of a configuration of an imaging element according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating an overall configuration of the image sensor illustrated in FIG. 1 . 2 is an equivalent circuit diagram of the image sensor shown in FIG. 1 . 2 is a schematic diagram showing the arrangement of transistors constituting a lower electrode and a control unit of the image sensor shown in FIG. 1 . 4 is a schematic cross-sectional view illustrating another example of the configuration of the imaging element according to the first embodiment of the present disclosure. FIG. 2A to 2C are cross-sectional views for explaining a method of manufacturing the image sensor shown in FIG. FIG. 7 is a cross-sectional view showing a process following FIG. 6. 8 is a cross-sectional view showing a process following FIG. 7 . 9 is a cross-sectional view showing a process following FIG. 8 . 10 is a cross-sectional view showing a process following FIG. 9 . 2 is a timing chart illustrating an example of an operation of the image sensor illustrated in FIG. 1 . 11 is a schematic cross-sectional view illustrating an example of a configuration of an imaging element according to a modified example of the present disclosure. 2 is a block diagram showing a configuration of an imaging device using the imaging element shown in FIG. 1 etc. as a pixel. FIG. 14 is a functional block diagram illustrating an example of an electronic device (camera) using the imaging device illustrated in FIG. 13 . 1 is a block diagram showing an example of a schematic configuration of an in-vivo information acquiring system. 1 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. 2 is a block diagram showing an example of the functional configuration of a camera head and a CCU. FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; 4 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit; FIG. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a device sample produced in Experiment 1.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspect. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The order of description is as follows.
1. Embodiment (Example of an imaging element including an organic photoelectric conversion unit having an organic layer containing a dipyrromethene derivative)
1-1. Configuration of the imaging element 1-2. Manufacturing method of the imaging element 1-3. Actions and effects 2. Modification (example in which three organic photoelectric conversion units are stacked on a semiconductor substrate)
3. Application examples 4. Application examples 5. Working examples

1. Preferred embodiment
FIG. 1 illustrates an example of a cross-sectional configuration of an imaging element (imaging element 10A) according to an embodiment of the present disclosure. FIG. 2 illustrates a planar configuration of the imaging element 10A illustrated in FIG. 1. FIG. 3 is an equivalent circuit diagram of the imaging element 10A illustrated in FIG. 1, which corresponds to the region 100 illustrated in FIG. 2. FIG. 4 illustrates a schematic diagram of a lower electrode 21 and an arrangement of transistors constituting a control unit of the imaging element 10A illustrated in FIG. 1. The imaging element 10A constitutes one pixel (unit pixel P) in an imaging device (imaging device 1; see FIG. 13) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras.

The imaging element 10A of the present embodiment is a vertical stack of two organic photoelectric conversion units 20 and 70 and one inorganic photoelectric conversion unit 32. The organic photoelectric conversion units 20 and 70 are each stacked in the order of a lower electrode 21, a photoelectric conversion layer 24 and an upper electrode 25, a lower electrode 71, a photoelectric conversion layer 74 and an upper electrode 75. The photoelectric conversion layer 74 detects either the infrared or visible range and is formed using a dipyrromethene derivative represented by general formula (1) or general formula (2) described below. This photoelectric conversion layer 74 corresponds to a specific example of an "organic layer" in this disclosure.

(1-1. Configuration of the image sensor)
As described above, the imaging element 10A is a so-called vertical spectroscopic imaging element in which two organic photoelectric conversion units 20 and 70 and one inorganic photoelectric conversion unit 32 are stacked in the vertical direction. The organic photoelectric conversion units 20 and 70 are stacked in this order on the first surface (rear surface; surface 30S1) side of the semiconductor substrate 30. The inorganic photoelectric conversion unit 32 is embedded in the semiconductor substrate 30. As described above, the organic photoelectric conversion unit 20 has a photoelectric conversion layer 24 formed of an organic material between the lower electrode 21 and the upper electrode 25 arranged opposite to each other. Similarly, the organic photoelectric conversion unit 70 has a photoelectric conversion layer 74 formed of an organic material between the lower electrode 71 and the upper electrode 75 arranged opposite to each other. These photoelectric conversion layers 24 and 74 are each configured to include a p-type semiconductor and an n-type semiconductor, and have a bulk heterojunction structure within the layer. A bulk heterojunction structure is a p/n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

The organic photoelectric conversion units 20, 70 and the inorganic photoelectric conversion unit 32G selectively detect light in different wavelength bands and perform photoelectric conversion. For example, the organic photoelectric conversion unit 20 acquires a green (G) color signal. For example, the organic photoelectric conversion unit 70 acquires a blue (B) color signal. For example, the inorganic photoelectric conversion unit 32 acquires a red (R) color signal. This makes it possible for the image sensor 10A to acquire multiple types of color signals in one pixel without using a color filter.

In this embodiment, we will explain the case where, of the pairs of electrons and holes (electron-hole pairs) generated by photoelectric conversion, the electrons are read out as signal charges (when the n-type semiconductor region is used as the photoelectric conversion layer). In the figures, the "+" (plus) next to "p" and "n" indicates that the p-type or n-type impurity concentration is high.

On the second surface (surface; 30S2) of the semiconductor substrate 30, for example, floating diffusions (floating diffusion layers) FD1 (region 36B1 in the semiconductor substrate 30), FD2 (region 36B2 in the semiconductor substrate 30), FD3 (region 38C in the semiconductor substrate 30), transfer transistor Tr3, amplifier transistors (modulation elements) AMP1, AMP2, AMP3, reset transistors RST1, RST2, RST3, and selection transistors SEL1, SEL2, SEL3 are provided. On the second surface (surface 30S2) of the semiconductor substrate 30, a multilayer wiring layer 40 is laminated. The multilayer wiring layer 40 has a configuration in which, for example, wiring layers 41, 42, 43 are laminated in an insulating layer 44.

In the drawings, the first surface (surface 30S1) of the semiconductor substrate 30 is represented as the light incident side S1, and the second surface (surface 30S2) is represented as the wiring layer side S2.

In the organic photoelectric conversion unit 20, the lower electrode 21, the semiconductor layer 23, the photoelectric conversion layer 24, and the upper electrode 25 are laminated in this order from the first surface (surface 30S1) side of the semiconductor substrate 30. In addition, an insulating layer 22 is provided between the lower electrode 21 and the semiconductor layer 23. The lower electrode 21 is formed separately for each image sensor 10A, and is composed of a readout electrode 21A and a storage electrode 21B separated from each other by the insulating layer 22, as will be described in detail later. Of the lower electrodes 21, the readout electrode 21A is electrically connected to the semiconductor layer 23 through an opening 22H provided in the insulating layer 22. In FIG. 1, the semiconductor layer 23, the photoelectric conversion layer 24, and the upper electrode 25 are shown as an example formed separately for each image sensor 10A, but may be provided as a continuous layer common to a plurality of image sensors 10A, for example.

The organic photoelectric conversion unit 70 is stacked above the organic photoelectric conversion unit 20, and similarly to the organic photoelectric conversion unit 20, a lower electrode 71, a semiconductor layer 73, a photoelectric conversion layer 74, and an upper electrode 75 are stacked in this order from the first surface (surface 30S1) side of the semiconductor substrate 30. An insulating layer 72 is provided between the lower electrode 71 and the semiconductor layer 73. The lower electrode 71 is, for example, formed separately for each image sensor 10A, and is composed of a readout electrode 71A and a storage electrode 71B separated from each other by the insulating layer 72. Of the lower electrodes 71, the readout electrode 71A is electrically connected to the photoelectric conversion layer 74 through an opening 72H provided in the insulating layer 72. In FIG. 1, an example in which the semiconductor layer 73, the photoelectric conversion layer 74, and the upper electrode 75 are formed separately for each image sensor 10A is shown, but they may be provided as a continuous layer common to a plurality of image sensors 10A, for example.

On the first surface (surface 30S1) of the semiconductor substrate 30, a dielectric film 26 and an insulating film 27 are provided in this order. In addition, between the semiconductor substrate 30 and the organic photoelectric conversion unit 20 (specifically, between the insulating film 27 and the organic photoelectric conversion unit 20) and between the organic photoelectric conversion unit 20 and the organic photoelectric conversion unit 70, for example, an interlayer insulating layer 28 is provided, and they are electrically insulated. On the upper electrode 75, a protective layer 51 is provided. In the protective layer 51, for example, a light-shielding film 52 is provided at a position corresponding to the readout electrode 21A and the readout electrode 71A. This light-shielding film 52 does not cover at least the storage electrode 21B and the storage electrode 71B, and may be provided so as to cover at least the areas of the readout electrodes 21A and 71A that are in direct contact with the semiconductor layers 23 and 73, respectively. Optical members such as a planarization layer (not shown) and an on-chip lens 53 are provided above the protective layer 51.

Between the first surface (surface 30S1) and the second surface (surface 30S2) of the semiconductor substrate 30, through-electrodes 34X and 34Y are provided. The through-electrode 34X is electrically connected to the readout electrode 21A of the organic photoelectric conversion unit 20, and the organic photoelectric conversion unit 20 is connected to the gate Gamp1 of the amplifier transistor AMP1 and one of the source/drain regions 36B1 of the reset transistor RST1, which also serves as the floating diffusion FD1, via the through-electrode 34X. The through-electrode 34Y is electrically connected to the readout electrode 71A of the organic photoelectric conversion unit 70, and the organic photoelectric conversion unit 70 is connected to the gate Gamp2 of the amplifier transistor AMP2 and one of the source/drain regions 36B2 of the reset transistor RST2, which also serves as the floating diffusion FD2, via the through-electrode 34Y. As a result, in the imaging element 10A, charges generated in the organic photoelectric conversion units 20, 70 on the first surface (surface 30S21) side of the semiconductor substrate 30 can be efficiently transferred to the second surface (surface 30S2) side of the semiconductor substrate 30, thereby improving characteristics.

The lower end of the through electrode 34X is connected to a connection portion 41A in the wiring layer 41, and the connection portion 41A and the gate Gamp1 of the amplifier transistor AMP1 are connected via a lower first contact 45A. The connection portion 41A and the floating diffusion FD1 (region 36B1) are connected, for example, via a lower second contact 46A. The upper end of the through electrode 34X is connected, for example, to the read electrode 21A via an upper first contact 29A, a pad portion 39A, and an upper second contact 29B.

The lower end of the through electrode 34Y is connected to the connection portion 41B in the wiring layer 41, and the connection portion 41B and the gate Gamp2 of the amplifier transistor AMP2 are connected via the lower 34 contact 45B. The connection portion 41B and the floating diffusion FD2 (region 36B2) are connected, for example, via the lower fourth contact 46B. The upper end of the through electrode 34Y is connected to the readout electrode 71A, for example, via the upper fourth contact 79A, the pad portion 69A, the upper fifth contact 79B, the pad portion 69B, and the upper sixth contact 79C. In addition, the storage electrode 71B of the lower electrode 71 constituting the organic photoelectric conversion unit 70 is connected to the pad portion 69C via the upper seventh contact 79D.

The through electrodes 34X and 34Y are provided, for example, for each of the organic photoelectric conversion units 20 and 70 in each of the image pickup elements 10A. The through electrodes 34X function as a connector between the organic photoelectric conversion unit 20 and the gate Gamp1 and floating diffusion FD1 of the amplifier transistor AMP1, and also serve as a transmission path for charges generated in the organic photoelectric conversion unit 20. The through electrodes 34Y function as a connector between the organic photoelectric conversion unit 70 and the gate Gamp2 and floating diffusion FD2 of the amplifier transistor AMP2, and also serve as a transmission path for charges generated in the organic photoelectric conversion unit 70.

The reset gate Grst1 of the reset transistor RST1 is disposed next to the floating diffusion FD1 (one of the source/drain regions 36B1 of the reset transistor RST1). This allows the charge stored in the floating diffusion FD1 to be reset by the reset transistor RST1. The reset gate Grst2 of the reset transistor RST2 is disposed next to the floating diffusion FD2 (one of the source/drain regions 36B2 of the reset transistor RST2). This allows the charge stored in the floating diffusion FD2 to be reset by the reset transistor RST2.

In the imaging element 10A of the present embodiment, light incident on the organic photoelectric conversion units 20 and 70 from the upper electrode 75 side is absorbed by the photoelectric conversion layers 24 and 74, respectively. The excitons generated by this move to the interface between the electron donor and electron acceptor constituting the photoelectric conversion layers 24 and 74, and are dissociated into excitons, that is, into electrons and holes. The charges (electrons and holes) generated here are transported to different electrodes by diffusion due to the difference in carrier concentration and by an internal electric field due to the difference in work function between the anode (e.g., the upper electrode 25 and 75) and the cathode (e.g., the lower electrode 21 and 71), and are detected as a photocurrent. In addition, the transport direction of the electrons and holes can be controlled by applying a potential between the lower electrode 21 and the upper electrode 25 and between the lower electrode 71 and the upper electrode 75, respectively.

The structure and materials of each part are explained below.

The organic photoelectric conversion units 20 and 70 are organic photoelectric conversion elements that absorb light corresponding to part or all of a selective wavelength band (e.g., 400 nm or more and 700 nm or less) and generate excitons (electron-hole pairs).

As described above, the lower electrode 21 is composed of a read electrode 21A and a storage electrode 21B that are formed separately. The read electrode 21A is for transferring the charge generated in the photoelectric conversion layer 24 to the floating diffusion FD1. The read electrode 21A is connected to the floating diffusion FD1 via, for example, the upper second contact 29B, the pad portion 39A, the upper first contact 29A, the through electrode 34X, the connection portion 41A, and the lower second contact 46. The storage electrode 21B is for storing electrons, which are generated in the photoelectric conversion layer 24, as signal charges in the semiconductor layer 23. The storage electrode 21B is provided in a region that covers the light receiving surface of the inorganic photoelectric conversion unit 32, facing the light receiving surface of the inorganic photoelectric conversion unit 32 formed in the semiconductor substrate 30. It is preferable that the storage electrode 21B is larger than the read electrode 21A. This allows a large amount of charge to be stored. As shown in FIG. 4, a voltage application circuit 60 is connected to the storage electrode 21B via wiring.

The lower electrode 21 is made of a conductive film having optical transparency. Examples of the material of the lower electrode 21 include indium tin oxide (ITO), In ₂ O ₃ with tin (Sn) added as a dopant, and indium tin oxide including crystalline ITO and amorphous ITO. In addition to the above, the material of the lower electrode 21 may be a tin oxide (SnO ₂ )-based material with a dopant added, or a zinc oxide-based material with a dopant added. Examples of the zinc oxide-based material include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Also, CuI, _InSbO4 , ZnMgO, _CuInO2 , _MgIN2O4 , CdO, _ZnSnO3 , _TiO2, etc. may be used as the constituent material of the lower electrode _21. Furthermore, a spinel type oxide _or an oxide having a _YbFe2O4 structure may also be used.

The semiconductor layer 23 is provided below the photoelectric conversion layer 24, specifically between the insulating layer 22 and the photoelectric conversion layer 24, and is for accumulating signal charges generated in the photoelectric conversion layer 24. The semiconductor layer 23 is preferably formed using a material that has a higher charge mobility and a larger band gap than the photoelectric conversion layer 24. For example, the band gap of the material constituting the semiconductor layer 23 is preferably 3.0 eV or more. Examples of such materials include oxide semiconductor materials such as IGZO and organic semiconductor materials. Examples of organic semiconductor materials include transition metal dichalcogenides, silicon carbide, diamond, graphene, carbon nanotubes, condensed polycyclic hydrocarbon compounds, and condensed heterocyclic compounds. The thickness of the semiconductor layer 23 is, for example, 10 nm or more and 300 nm or less. By providing the semiconductor layer 23 made of the above material below the photoelectric conversion layer 24, it is possible to prevent recombination of charges during charge accumulation and improve transfer efficiency.

The photoelectric conversion layer 24 is for converting light energy into electrical energy. The photoelectric conversion layer 24 of this embodiment absorbs, for example, a part or all of the light in the range of the green band of 500 nm to 600 nm. The photoelectric conversion layer 24 is composed of, for example, two or more organic materials that function as p-type semiconductors or n-type semiconductors. The photoelectric conversion layer 24 has a junction surface (p/n junction surface) between a p-type semiconductor and an n-type semiconductor within the layer. The p-type semiconductor functions relatively as an electron donor (donor), and the n-type semiconductor functions relatively as an electron acceptor (acceptor). The photoelectric conversion layer 24 provides a place where excitons generated when light is absorbed separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p/n junction surface) between the electron donor and the electron acceptor.

In addition to the p-type semiconductor and the n-type semiconductor, the photoelectric conversion layer 24 may further include an organic material, so-called dye material, that photoelectrically converts light in a predetermined wavelength band while transmitting light in other wavelength bands. When the photoelectric conversion layer 24 is formed using three types of organic materials, the p-type semiconductor, the n-type semiconductor, and the dye material, it is preferable that the p-type semiconductor and the n-type semiconductor are materials that have optical transparency in the visible range (e.g., 400 nm to 700 nm). The thickness of the photoelectric conversion layer 24 is, for example, 25 nm to 400 nm, preferably 50 nm to 350 nm. More preferably, it is 150 nm to 300 nm.

The photoelectric conversion layer 24 is formed by containing, as a dye material, for example, subphthalocyanine, dipyrromethene, merocyanine, squarylium, or derivatives thereof, which absorb light in a wavelength band of 500 nm or more and 600 nm or less. As the other organic material constituting the photoelectric conversion layer 24, as described above, it is preferable that the material has optical transparency in the visible region (for example, 400 nm to 700 nm), and for example, C ₆₀ fullerene or its derivative represented by formula (4) described later, or C ₇₀ fullerene or its derivative represented by formula (5) described later is included. Furthermore, as the other organic material constituting the photoelectric conversion layer 24, it is preferable to use, for example, a material having hole transport properties, and specifically, for example, thiophene derivatives, anthracene derivatives, tetracene derivatives, etc., which are represented by formulas (6-1) to (6-17) described later are included. In addition, R in formulas (6-1) to (6-17) is each independently a hydrogen atom, a halogen atom, an amino group, an alkoxy group, an acylamino group, a carboxy group, an ester group, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, or a substituted or unsubstituted aryl group or heteroaryl group having 4 to 30 carbon atoms.

Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

The upper electrode 25 is made of a conductive film having optical transparency, similar to the lower electrode 21. In an imaging device 1 using the imaging element 10A as one pixel, the upper electrode 25 may be separated for each pixel, or may be formed as an electrode common to each pixel. The thickness of the upper electrode 25 is, for example, 10 nm to 200 nm.

The lower electrode 71, the semiconductor layer 73 and the upper electrode 75 have the same configuration as the lower electrode 21, the semiconductor layer 23 and the upper electrode 25 described above, respectively, and can be formed, for example, using the same materials.

The photoelectric conversion layer 74 is for converting light energy into electrical energy, and absorbs, for example, some or all of the light in the blue band between 400 nm and 500 nm. Specifically, the photoelectric conversion layer 74 is an organic layer having an absorptivity of 70% or more at a wavelength of 450 nm and less than 20% at a wavelength between 560 nm and 700 nm, and can be formed, for example, using an organic material described later.

Like photoelectric conversion layer 24, photoelectric conversion layer 74 is composed of two or more organic materials that function as p-type or n-type semiconductors, and has a junction surface between a p-type semiconductor and an n-type semiconductor (p/n junction surface) within the layer.

In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 74 further includes an organic material, a so-called dye material, that photoelectrically converts light in the blue wavelength band while transmitting light in other wavelength bands. When the photoelectric conversion layer 74 is formed using three types of organic materials, the p-type semiconductor, the n-type semiconductor, and the dye material, it is preferable that the p-type semiconductor and the n-type semiconductor are materials that have optical transparency in the visible range (e.g., 400 nm to 700 nm). The thickness of the photoelectric conversion layer 74 is, for example, 25 nm to 400 nm, and preferably 50 nm to 350 nm. More preferably, it is 150 nm to 300 nm.

In this embodiment, the photoelectric conversion layer 74 is formed by including, as a dye material, for example, a dipyrromethene derivative represented by the following general formula (1) or general formula (2). The dipyrromethene derivative represented by general formula (1) or general formula (2) is, for example, a BODIPY dye that has electron accepting properties and absorbs light of, for example, 400 nm or more and 500 nm or less.

（Ｘは、酸素原子または硫黄原子である。Ｒ，Ｒ’は、各々独立して、置換または無置換の直鎖アルキル基、分岐アルキル基、環状アルキル基、フルオロアルキル基、アリール基およびヘテロアリール基から選択される。Ｙ１～Ｙ６，Ｙ’１～Ｙ’６は、各々独立して、水素原子、ハロゲン原子、直鎖アルキル基、分岐アルキル基、環状アルキル基、チオアルキル基、チオアリール基、アリールスルホニル基、アルキルスルホニル基、アミノ基、アルキルアミノ基、アリールアミノ基、ヒドロキシ基、アルコキシ基、アシルアミノ基、アシルオキシ基、アリール基、ヘテロアリール基、カルボキシ基、カルボキソアミド基、カルボアルコキシ基、アシル基、スルホニル基、シアノ基およびニトロ基から選択される。Ｙ７，Ｙ８は、各々独立して、ハロゲン原子、直鎖アルキル基、分岐アルキル基、環状アルキル基、フルオロアルキル基、アミノ基、アルコキシ基、アルキルチオ基、アシルアミノ基、アシルオキシ基、アリール基、ヘテロアリール基、アミド基、アシル基、スルホニル基およびシアノ基から選択される。Ｚは、ホウ素原子または金属原子である。）

(X is an oxygen atom or a sulfur atom. R and R' are each independently selected from a substituted or unsubstituted linear alkyl group, branched alkyl group, cyclic alkyl group, fluoroalkyl group, aryl group, and heteroaryl group. Y1 to Y6 and Y'1 to Y'6 are each independently a hydrogen atom, a halogen atom, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an alkylsulfonyl group, an amino group, an alkylamino group, an arylamino group, a hydroxy group, an alkoxy group, or an acylamino group. , an acyloxy group, an aryl group, a heteroaryl group, a carboxy group, a carboxamido group, a carboalkoxy group, an acyl group, a sulfonyl group, a cyano group, and a nitro group. Y7 and Y8 are each independently selected from a halogen atom, a straight-chain alkyl group, a branched alkyl group, a cyclic alkyl group, a fluoroalkyl group, an amino group, an alkoxy group, an alkylthio group, an acylamino group, an acyloxy group, an aryl group, a heteroaryl group, an amide group, an acyl group, a sulfonyl group, and a cyano group. Z is a boron atom or a metal atom.

The metal atom is any one of magnesium, calcium, aluminum, nickel, cobalt, iron, palladium, copper, zinc, gallium, tin, iridium, platinum, silicon, and phosphorus. Specific examples of the dipyrromethene derivative represented by the above general formula (1) include the compounds represented by the following formulas (1-1) to (1-24).

Specific examples of the dipyrromethene derivative represented by the above general formula (2) include the compounds represented by the following formulas (2-1) to (2-6).

As the other organic material constituting the photoelectric conversion layer 74, as described above, it is preferable that the material has optical transparency in the visible region (for example, 400 nm to 700 nm), and for example, C ₆₀ fullerene or its derivative represented by the following formula (4), or C ₇₀ fullerene or its derivative represented by the following formula (5) is used. Furthermore, as the other organic material constituting the photoelectric conversion layer 24, it is preferable to use a material having hole transport properties, and specifically, for example, thiophene derivatives, anthracene derivatives, tetracene derivatives, etc. represented by the following formulas (6-1) to (6-17) are used. Note that R in formulas (6-1) to (6-17) is each independently a hydrogen atom, a halogen atom, an amino group, an alkoxy group, an acylamino group, a carboxy group, an ester group, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, or a substituted or unsubstituted aryl group or heteroaryl group having 4 to 30 carbon atoms.

Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

Other layers may be provided between the semiconductor layer 23 and the photoelectric conversion layer 24, between the photoelectric conversion layer 24 and the upper electrode 25, and between the semiconductor layer 73 and the photoelectric conversion layer 74, and between the photoelectric conversion layer 74 and the upper electrode 75.

5, the organic photoelectric conversion unit 20 may have a configuration in which, for example, a semiconductor layer 23, a hole blocking layer 24A, a photoelectric conversion layer 24, and an electron blocking layer 24B are stacked in this order from the lower electrode 21 side. The organic photoelectric conversion unit 70 may have a configuration in which, for example, a semiconductor layer 73, a hole blocking layer 74A (first charge blocking layer), a photoelectric conversion layer 74, and an electron blocking layer 74B (second charge blocking layer) are stacked in this order from the lower electrode 71 side.

Furthermore, for example, an undercoat layer or a hole transport layer may be provided between the lower electrode 21 and the photoelectric conversion layer 24 and between the lower electrode 71 and the photoelectric conversion layer 74. A work function adjustment layer, a buffer layer, or an electron transport layer may be provided between the photoelectric conversion layer 24 and the upper electrode 25 and between the photoelectric conversion layer 74 and the upper electrode 75.

The insulating layers 22 and 72 are for electrically isolating the storage electrode 21B from the semiconductor layer 23, and the storage electrode 71B from the semiconductor layer 73, respectively. The insulating layer 22 is provided, for example, in the interlayer insulating layer 28 so as to cover the lower electrode 21. In addition, the insulating layer 22 has an opening 22H on the read electrode 21A of the lower electrode 21, and the read electrode 21A and the semiconductor layer 23 are electrically connected through this opening 22H. The insulating layer 72 is provided, for example, on the interlayer insulating layer 28 so as to cover the lower electrode 71. In addition, the insulating layer 72 has an opening 72H on the read electrode 71A of the lower electrode 71, and the read electrode 71A and the semiconductor layer 23 are electrically connected through this opening 72H.

The insulating layers 22 and 72 are each formed of a single layer of one of silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon oxynitride (SiON), etc., or a laminated film of two or more of these materials. The thickness of the insulating layers 22 and 72 is, for example, 20 nm to 500 nm.

The dielectric film 26 is intended to prevent light reflection caused by the difference in refractive index between the semiconductor substrate 30 and the insulating film 27. The material of the dielectric film 26 is preferably a material having a refractive index between the refractive index of the semiconductor substrate 30 and the refractive index of the insulating film 27. Furthermore, the material of the dielectric film 26 is preferably a material capable of forming a film having a negative fixed charge. Alternatively, the material of the dielectric film 26 is preferably a semiconductor material or a conductive material having a wider band gap than the semiconductor substrate 30. This makes it possible to suppress the generation of dark current at the interface of the semiconductor substrate 30. Such materials include hafnium oxide (HfO _x ), aluminum oxide (AlO _x ), zirconium oxide (ZrO _x ), tantalum oxide (TaO _x ), titanium oxide (TiO _x ), lanthanum oxide (LaO _x ), praseodymium oxide (PrO _x ), cerium oxide (CeO _x ), neodymium oxide (NdO _x ), promethium oxide (PmO _x ), samarium oxide (SmO _x ), europium oxide (EuO _x ), gadolinium oxide (GdO _x ), terbium oxide (TbO _x ), dysprosium oxide (DyO _x ), holmium oxide (HoO _x ), thulium oxide (TmO _x ), ytterbium oxide (YbO _x ), lutetium oxide (LuO _x ), yttrium oxide (YO _x ), hafnium nitride (HfN _x ), aluminum nitride (AlN _{x )} , ), hafnium oxynitride (HfO _x N _y ), and aluminum oxynitride (AlO _x N _y ).

The insulating film 27 is provided on the dielectric film 26 formed on the first surface (surface 30S1) of the semiconductor substrate 30 and on the side surfaces of the through holes 30H1, 30H2, and serves to electrically insulate the through electrodes 34X, 34Y from the semiconductor substrate 30. Examples of materials for the insulating film 27 include silicon oxide (SiO _x ), TEOS, silicon nitride (SiN _x ), and silicon oxynitride (SiON).

The interlayer insulating layer 28 is configured, for example, as a single layer film made of one of silicon oxide (SiO _x ), TEOS, silicon nitride (SiN _x ), silicon oxynitride (SiON), etc., or as a laminate film made of two or more of these materials.

The protective layer 51 is made of a light-transmitting material, and is, for example, a single layer film made of any one of silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon oxynitride (SiON), etc., or a laminate film made of two or more of these materials. The thickness of the protective layer 51 is, for example, 100 nm to 30,000 nm.

The semiconductor substrate 30 is, for example, an n-type silicon (Si) substrate, and has a p-well 31 in a predetermined region (for example, pixel portion 1a). The second surface (surface 30S2) of the p-well 31 is provided with the transfer transistor Tr3, amplifier transistors AMP1, AMP2, AMP3, reset transistors RST1, RST2, RST3, and selection transistors SEL1, SEL2, SEL3, etc., described above. In addition, the peripheral portion (peripheral portion 1b) of the semiconductor substrate 30 is provided with, for example, a pixel readout circuit 110 and a pixel drive circuit 120, which are composed of logic circuits, etc., as shown in FIG. 2.

The reset transistor RST1 (reset transistor TR1rst) and the reset transistor RST2 (reset transistor TR2rst) reset, for example, the charges transferred from the organic photoelectric conversion units 20 and 70 to the floating diffusions FD1 and FD2, respectively, and are composed of, for example, MOS transistors.

Specifically, the reset transistor TR1rst is composed of a reset gate Grst1, a channel formation region 36A1, and source/drain regions 36B1 and 36C1. The reset gate Grst1 is connected to a reset line RST1, and one of the source/drain regions 36B1 of the reset transistor TR1rst also serves as a floating diffusion FD1. The other of the source/drain regions 36C1 constituting the reset transistor TR1rst is connected to a power supply line VDD. The reset transistor TR2rst is composed of a reset gate Grst2, a channel formation region 36A2, and source/drain regions 36B2 and 36C2. The reset gate Grst2 is connected to a reset line RST2, and one of the source/drain regions 36B2 of the reset transistor TR2rst also serves as a floating diffusion FD2. The other source/drain region 36C2 constituting the reset transistor TR2rst is connected to the power supply line VDD.

The amplifier transistor AMP1 (amplifier transistor TR1amp) and the amplifier transistor AMP2 (amplifier transistor TR2amp) are, for example, modulation elements that modulate the amount of charge generated in the organic photoelectric conversion units 20 and 70, respectively, into a voltage, and are, for example, composed of a MOS transistor.

Specifically, the amplifier transistor TR1amp is composed of a gate Gamp1, a channel formation region 35A1, and source/drain regions 35B1 and 35C1. The gate Gamp1 is connected to the read electrode 21A and one of the source/drain regions 36B1 (floating diffusion FD1) of the reset transistor Tr1rst via the lower first contact 45A, the connection portion 41A, the lower second contact 46A, the through electrode 34X, etc. In addition, one of the source/drain regions 35B1 shares an area with the other of the source/drain regions 36C1 constituting the reset transistor Tr1rst, and is connected to the power line VDD. The amplifier transistor TR2amp is composed of a gate Gamp2, a channel formation region 35A2, and source/drain regions 35B2 and 35C2. The gate Gamp2 is connected to the read electrode 71A and one of the source/drain regions 36B2 (floating diffusion FD2) of the reset transistor Tr2rst via the lower third contact 45B, the connection portion 42B, the lower fourth contact 46B, the through electrode 34Y, the upper fourth contact 79A, the pad portion 69A, the upper fifth contact 79B, the pad portion 69B, and the upper sixth contact 79C. The one of the source/drain regions 35B2 shares an area with the other of the source/drain regions 36C2 constituting the reset transistor Tr2rst, and is connected to the power supply line VDD.

The selection transistor SEL1 (selection transistor TR1sel) is composed of a gate Gsel1, a channel formation region 34A1, and source/drain regions 34B1 and 34C1. The gate Gsel1 is connected to the selection line SEL1. One source/drain region 34B1 shares an area with the other source/drain region 35C1 constituting the amplifier transistor AMP1, and the other source/drain region 34C1 is connected to the signal line (data output line) VSL1. The selection transistor SEL2 (selection transistor TR2sel) is composed of a gate Gsel2, a channel formation region 34A2, and source/drain regions 34B2 and 34C2. The gate Gsel2 is connected to the selection line SEL2. One source/drain region 34B2 shares an area with the other source/drain region 35C2 constituting the amplifier transistor AMP2, and the other source/drain region 34C2 is connected to a signal line (data output line) VSL2.

The inorganic photoelectric conversion unit 32 has a pn junction in a predetermined region of the semiconductor substrate 30. The inorganic photoelectric conversion unit 32 selectively detects red light and accumulates a signal charge corresponding to the red color. Note that red (R) is a color corresponding to a wavelength band of, for example, 620 nm or more and 750 nm or less. The inorganic photoelectric conversion unit 32 may be capable of detecting some or all of the light in the red band of, for example, 620 nm to 750 nm.

The inorganic photoelectric conversion unit 32 is configured to include, for example, a p+ region that serves as a hole accumulation layer and an n region that serves as an electron accumulation layer (having a p-n-p layered structure).

The transfer transistor Tr3 (transfer transistor TR3trs) transfers the signal charge corresponding to red generated and accumulated in the inorganic photoelectric conversion unit 32 to the floating diffusion FD3, and is composed of, for example, a MOS transistor. The transfer transistor TR3trs is connected to a transfer gate line TG3. Furthermore, a floating diffusion FD3 is provided in the region 38C near the gate Gtrs3 of the transfer transistor TR3trs. The charge accumulated in the inorganic photoelectric conversion unit 32 is read out to the floating diffusion FD3 via a transfer channel formed along the gate Gtrs3.

Further provided on the second surface (surface 30S2) of the semiconductor substrate 30 are a reset transistor TR3rst, an amplifier transistor TR3amp, and a selection transistor TR3sel which constitute the control unit of the inorganic photoelectric conversion unit 32.

The reset transistor TR3rst is composed of a gate, a channel formation region, and a source/drain region. The gate of the reset transistor TR3rst is connected to the reset line RST3, and one of the source/drain regions constituting the reset transistor TR3rst is connected to the power supply line VDD. The other source/drain region constituting the reset transistor TR3rst also serves as the floating diffusion FD3.

The amplifier transistor TR3amp is composed of a gate, a channel formation region, and a source/drain region. The gate is connected to the other source/drain region (floating diffusion FD3) constituting the reset transistor TR3rst. In addition, one of the source/drain regions constituting the amplifier transistor TR3amp shares an area with one of the source/drain regions constituting the reset transistor TR3rst, and is connected to the power supply line VDD.

The selection transistor TR3sel is composed of a gate, a channel formation region, and a source/drain region. The gate is connected to the selection line SEL3. One of the source/drain regions constituting the selection transistor TR3sel shares an area with the other source/drain region constituting the amplifier transistor TR3amp. The other source/drain region constituting the selection transistor TR3sel is connected to a signal line (data output line) VSL3.

The reset lines RST1, RST2, and RST3, the selection lines SEL1, SEL2, and SEL3, and the transfer gate line TG3 are each connected to a vertical drive circuit 112 that constitutes a drive circuit. The signal lines (data output lines) VSL1, VSL2, and VSL3 are connected to a column signal processing circuit 113 that constitutes a drive circuit.

The lower first contact 45A, the lower second contact 46A, the lower third contact 45B, the lower fourth contact 46B, the upper first contact 29A, the upper second contact 29B, the upper third contact 29C, the upper fourth contact 79A, the upper fifth contact 79B and the upper sixth contact 79C are made of, for example, a doped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon), or a metal material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), tantalum (Ta), etc.

(1-2. Manufacturing method of image sensor)
The imaging element 10A of the present embodiment can be manufactured, for example, as follows.

6 to 10 show the manufacturing method of the image sensor 10A in the order of steps. First, as shown in Fig. 6, a well of a first conductivity type, for example a p-well 31, is formed in a semiconductor substrate 30, and an inorganic photoelectric conversion section 32 of a second conductivity type (for example n-type) is formed in this p-well 31. A p+ region is formed near the first surface (surface 30S1) of the semiconductor substrate 30.

6, n+ regions that will become floating diffusions FD1 to FD3 are formed on the second surface (surface 30S2) of the semiconductor substrate 30, and then a gate insulating layer 33 and a gate wiring layer 47 including the gates of the transfer transistor Tr3, the selection transistors SEL1, SEL2, and SEL3, the amplifier transistors AMP1, AMP2, and AMP3, and the reset transistors RST1, RST2, and RST3 are formed. Furthermore, a multilayer wiring layer 40 consisting of wiring layers 41 to 43 and an insulating layer 44 including a lower first contact 45A, a lower second contact 46A, a lower third contact 45B, a lower fourth contact 46B, and connection portions 41A and 41B is formed on the second surface (surface 30S2) of the semiconductor substrate 30.

The base of the semiconductor substrate 30 is, for example, an SOI (Silicon on Insulator) substrate in which the semiconductor substrate 30, a buried oxide film (not shown), and a holding substrate (not shown) are stacked. The buried oxide film and the holding substrate are bonded to the first surface (surface 30S1) of the semiconductor substrate 30, although they are not shown in FIG. 6. After the ion implantation, an annealing process is performed.

Next, a support substrate (not shown) or another semiconductor substrate is bonded to the second surface (surface 30S2) side (multilayer wiring layer 40 side) of the semiconductor substrate 30, and the substrate is inverted. Next, the semiconductor substrate 30 is separated from the buried oxide film of the SOI substrate and the holding substrate, and the first surface (surface 30S1) of the semiconductor substrate 30 is exposed. The above steps can be performed using techniques used in normal CMOS processes, such as ion implantation and CVD (Chemical Vapor Deposition).

7, the semiconductor substrate 30 is processed from the first surface (surface 30S1) side by, for example, dry etching to form, for example, annular through holes 30H1 and 30H2. As shown in FIG. 7, the depth of the through holes 30H1 and 30H2 penetrates from the first surface (surface 30S1) to the second surface (surface 30S2) of the semiconductor substrate 30 and reaches, for example, the connection portions 41A and 41B.

8, a dielectric film 26 is formed on the first surface (surface 30S1) of the semiconductor substrate 30 and the side surfaces of the through holes 30H1 and 30H2, for example, by atomic layer deposition (ALD). As a result, a dielectric film 26 is formed that is continuous with the first surface (surface 30S1) of the semiconductor substrate 30 and the side and bottom surfaces of the through holes 30H1 and 30H2. Next, an insulating film 27 is formed on the first surface (surface 30S1) of the semiconductor substrate 30 and in the through holes 30H1 and 30H2, and then the insulating film 27 and the dielectric film 26 formed at the bottom of the through holes 30H1 and 30H2 are removed by, for example, dry etching to expose the connection portions 41A and 41B. At this time, the insulating film 27 on the first surface (surface 30S1) is also thinned. Next, a conductive film is formed on the insulating film 27 and in the through holes 30H1 and 30H2, and then a photoresist PR is formed at a predetermined position on the conductive film. Next, etching is performed and the photoresist PR is removed. As a result, the through electrodes 34X and 34Y having protruding portions are formed on the first surface (surface 30S1) of the semiconductor substrate 30.

9, an insulating film constituting the interlayer insulating layer 28 is formed on the insulating film 27 and the through electrodes 34X and 34Y, and then the upper first contact 29A, the pad portion 39A, and the upper second contact 29B are formed on the through electrode 34X, and the pad portion 39B and the upper third contact 29C are formed at a predetermined position. Furthermore, although not shown, the upper fourth contact 79A and the pad portion 69A are formed on the through electrode 34Y, and the surface of the interlayer insulating layer 28 is planarized using a chemical mechanical polishing (CMP) method. Next, a conductive film 21x is formed on the interlayer insulating layer 28, and then a photoresist is formed at a predetermined position of the conductive film 21x.

Next, as shown in Figure 10, the read electrode 21A and the storage electrode 21B are formed by etching and removing the photoresist.

After that, an insulating layer 22 is formed on the interlayer insulating layer 28 and the readout electrode 21A and storage electrode 21B, and an opening 22H is provided on the readout electrode 21A. Next, the semiconductor layer 23, the photoelectric conversion layer 24, and the upper electrode 25 are formed in this order on the insulating layer 22, and the organic photoelectric conversion section 70 is formed in the same manner. Finally, a protective layer 51, a light-shielding film 52, and an on-chip lens 53 are disposed on the upper electrode 75. With the above steps, the image sensor 10A shown in FIG. 1 is completed.

In addition, when forming the semiconductor layers 23, 73 and other organic layers using organic materials, it is desirable to form them continuously in a vacuum process (in a vacuum integrated process). In addition, the method of forming the photoelectric conversion layers 24, 74 is not necessarily limited to a method using a vacuum deposition method, and other methods, such as a spin coating technique or a printing technique, may be used. Furthermore, the method of forming the transparent electrodes (lower electrodes 21, 71 and upper electrodes 25, 75) depends on the material constituting the transparent electrodes, but may include physical vapor deposition methods (PVD methods) such as vacuum deposition methods, reactive deposition methods, various sputtering methods, electron beam deposition methods, and ion plating methods, pyrosol methods, methods of thermally decomposing organometallic compounds, spray methods, dip methods, and various chemical vapor deposition methods (CVD methods) including MOCVD methods, electroless plating methods, and electrolytic plating methods.

In the imaging element 10A, when light is incident through the organic photoelectric conversion unit 70 and the on-chip lens 53, the light passes through the organic photoelectric conversion unit 70, the organic photoelectric conversion unit 20, and the inorganic photoelectric conversion unit 32 in that order, and is photoelectrically converted into blue, green, and red light in the process of passing through. The signal acquisition operation for each color is described below.

(Acquisition of green and blue signals by organic photoelectric conversion units 20 and 70)
Of the light incident on the imaging element 10A, blue light is first selectively detected (absorbed) by the organic photoelectric conversion section 70 and photoelectrically converted.

The organic photoelectric conversion unit 70 is connected to the gate Gamp2 of the amplifier transistor AMP2 and the floating diffusion FD2 via the through electrode 34Y. Therefore, the electrons of the electron-hole pairs generated in the organic photoelectric conversion unit 70 are extracted from the lower electrode 71 side, transferred to the second surface (surface 30S2) of the semiconductor substrate 30 via the through electrode 34Y, and stored in the floating diffusion FD2. At the same time, the amount of charge generated in the organic photoelectric conversion unit 70 is modulated into a voltage by the amplifier transistor AMP2.

In addition, the reset gate Grst2 of the reset transistor RST2 is disposed next to the floating diffusion FD2. This allows the charge stored in the floating diffusion FD2 to be reset by the reset transistor RST2.

Next, of the light that passes through the organic photoelectric conversion unit 70, green light is selectively detected (absorbed) in the organic photoelectric conversion unit 20 and undergoes photoelectric conversion.

The organic photoelectric conversion unit 20 is connected to the gate Gamp1 of the amplifier transistor AMP1 and the floating diffusion FD1 via the through electrode 34X. Thus, the electrons of the electron-hole pairs generated in the organic photoelectric conversion unit 20 are extracted from the lower electrode 21 side, transferred to the second surface (surface 30S2) side of the semiconductor substrate 30 via the through electrode 34X, and stored in the floating diffusion FD1. At the same time, the amount of charge generated in the organic photoelectric conversion unit 20 is modulated into a voltage by the amplifier transistor AMP1.

In addition, the reset gate Grst1 of the reset transistor RST1 is disposed next to the floating diffusion FD1. As a result, the charge accumulated in the floating diffusion FD1 is reset by the reset transistor RST1.

Here, the organic photoelectric conversion units 20, 70 are connected not only to the amplifier transistors AMP1, AMP2 but also to the floating diffusions FD1, FD2 via the through electrodes 34X, 34Y, respectively, so that the charges accumulated in the floating diffusions FD1, FD2 can be easily reset by the reset transistors RST1, RST2.

On the other hand, if the through electrode 34X and the floating diffusion FD1, and the through electrode 34Y and the floating diffusion FD are not connected, respectively, it becomes difficult to reset the charge accumulated in the floating diffusions FD1 and FD2, and a large voltage is applied to pull it out to the upper electrodes 25 and 75. This may damage the photoelectric conversion layers 24 and 74. In addition, a structure that allows resetting in a short time would increase dark noise, which is a trade-off, making this structure difficult to implement.

Figure 11 shows an example of operation of the image sensor 10A, for example, in the organic photoelectric conversion unit 20. (A) shows the potential at the storage electrode 21B, (B) shows the potential at the floating diffusion FD1 (readout electrode 21A), and (C) shows the potential at the gate (Gsel) of the reset transistor TR1rst. In the image sensor 10A, voltages are applied to the readout electrode 21A and the storage electrode 21B individually.

In the image sensor 10A, during the accumulation period, a potential V1 is applied from the drive circuit to the readout electrode 21A, and a potential V2 is applied to the storage electrode 21B. Here, the potentials V1 and V2 are set to V2>V1. As a result, the charge (signal charge; electrons) generated by photoelectric conversion is attracted to the storage electrode 21B and accumulated in the region of the semiconductor layer 23 facing the storage electrode 21B (accumulation period). Incidentally, the potential of the region of the semiconductor layer 23 facing the storage electrode 21B becomes more negative as the photoelectric conversion time passes. Note that the holes are sent from the upper electrode 25 to the drive circuit.

In the image sensor 10A, a reset operation is performed in the latter part of the accumulation period. Specifically, at timing t1, the scanning unit changes the voltage of the reset signal RST from low to high. This causes the reset transistor TR1rst in the unit pixel P to turn on, and as a result, the voltage of the floating diffusion FD1 is set to the power supply voltage and the voltage of the floating diffusion FD1 is reset (reset period).

After the reset operation is completed, the charge is read out. Specifically, at timing t2, the drive circuit applies a potential V3 to the readout electrode 21A, and a potential V4 to the storage electrode 21B. Here, the potentials V3 and V4 are V3<V4. As a result, the charge stored in the region corresponding to the storage electrode 21B is read out from the readout electrode 21A to the floating diffusion FD1. That is, the charge stored in the semiconductor layer 23 is read out to the control unit (transfer period).

After the read operation is completed, the drive circuit again applies potential V1 to the read electrode 21A and potential V2 to the storage electrode 21B. As a result, the charge generated by the photoelectric conversion is attracted to the storage electrode 21B and stored in the region of the photoelectric conversion layer 24 facing the storage electrode 21B (storage period).

The organic photoelectric conversion unit 70 also operates in the same manner as the organic photoelectric conversion unit 20 described above.

(Acquisition of Red Signal by Inorganic Photoelectric Conversion Unit 32G)
Subsequently, the light (e.g., red light) transmitted through the organic photoelectric conversion units 20 and 70 is absorbed and photoelectrically converted in the inorganic photoelectric conversion unit 32. In the inorganic photoelectric conversion unit 32, electrons corresponding to the incident red light are accumulated in the n region of the inorganic photoelectric conversion unit 32, and the accumulated electrons are transferred to the floating diffusion FD3 by the transfer transistor Tr3.

(1-3. Actions and Effects)
In recent years, there has been a demand for the development of a vertical spectral image sensor including a bulk hetero-type organic photoelectric conversion layer capable of selectively and highly efficiently converting photoelectrically a predetermined wavelength band, particularly the blue band.

In contrast, in the present embodiment, a dipyrromethene derivative represented by the above general formula (1) or general formula (2), in which a specific substituent is directly bonded to the meso position of the dipyrromethene skeleton, is used to form, for example, photoelectric conversion layer 74. This results in the formation of photoelectric conversion layer 74 that selectively absorbs light in the blue band and has a high light absorption coefficient. In photoelectric conversion layer 74, excitons generated by the absorption of blue light are quickly dissociated into electrons and holes, and these charges can be transported quickly to the corresponding electrodes without recombination.

As a result, in this embodiment, it is possible to provide an imaging element 10A having high external quantum efficiency for blue light and an imaging device 1 equipped with the same.

Next, a modified example of the present disclosure will be described. In the following, components similar to those in the above embodiment will be given the same reference numerals, and their description will be omitted as appropriate.

2. Modifications
12 illustrates a cross-sectional configuration of an image sensor (image sensor 10C) according to a modified example of the present disclosure. The image sensor 10C constitutes one pixel (unit pixel P) in an image sensor 1 such as a complementary metal oxide semiconductor (CMOS) image sensor used in electronic devices such as digital still cameras and video cameras. The image sensor 10C of this embodiment has a configuration in which a red photoelectric conversion unit 90R, a green photoelectric conversion unit 90G, and a blue photoelectric conversion unit 90B formed using organic materials are stacked in this order on a semiconductor substrate 80 via an insulating layer 96.

The red photoelectric conversion unit 90R, the green photoelectric conversion unit 90G and the blue photoelectric conversion unit 90B each have an organic photoelectric conversion layer 92R, 92G, 92B between a pair of electrodes, specifically, between the first electrode 91R and the second electrode 93R, between the first electrode 91G and the second electrode 93G, and between the first electrode 91B and the second electrode 93B, respectively.

On the blue photoelectric conversion unit 90B, an on-chip lens 98L is provided via a protective layer 97 and an on-chip lens layer 98. A red storage layer 810R, a green storage layer 810G, and a blue storage layer 810B are provided in the semiconductor substrate 80. Light incident on the on-chip lens 98L is photoelectrically converted by the red photoelectric conversion unit 90R, the green photoelectric conversion unit 90G, and the blue photoelectric conversion unit 90B, and signal charges are sent from the red photoelectric conversion unit 90R to the red storage layer 810R, from the green photoelectric conversion unit 90G to the green storage layer 810G, and from the blue photoelectric conversion unit 90B to the blue storage layer 810B. The signal charges may be either electrons or holes generated by photoelectric conversion, but the following will be described as an example in which electrons are read out as signal charges.

The semiconductor substrate 80 is, for example, a p-type silicon substrate. The red storage layer 810R, the green storage layer 810G, and the blue storage layer 810B provided on the semiconductor substrate 80 each include an n-type semiconductor region, in which signal charges (electrons) supplied from the red photoelectric conversion unit 90R, the green photoelectric conversion unit 90G, and the blue photoelectric conversion unit 90B are accumulated. The n-type semiconductor regions of the red storage layer 810R, the green storage layer 810G, and the blue storage layer 810B are formed, for example, by doping the semiconductor substrate 80 with n-type impurities such as phosphorus (P) or arsenic (As). The semiconductor substrate 80 may be provided on a support substrate (not shown) made of glass or the like.

The semiconductor substrate 80 is provided with pixel transistors for reading out electrons from the red storage layer 810R, the green storage layer 810G, and the blue storage layer 810B, and transferring them to, for example, a vertical signal line (for example, the vertical signal line Lsig in FIG. 13 described below). The floating diffusions of these pixel transistors are provided in the semiconductor substrate 80, and these floating diffusions are connected to the red storage layer 810R, the green storage layer 810G, and the blue storage layer 810B. The floating diffusions are made of n-type semiconductor regions.

The insulating layer 96 is, for example, a single layer film made of one of silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon oxynitride (SiON), and hafnium oxide (HfO _x ), or a laminated film made of two or more of these. The insulating layer 96 may also be formed using an organic insulating material. Although not shown, the insulating layer 96 is provided with plugs and electrodes for connecting the red storage layer 810R and the red photoelectric conversion unit 90R, the green storage layer 810G and the green photoelectric conversion unit 90G, and the blue storage layer 810B and the blue photoelectric conversion unit 90B, respectively.

The red photoelectric conversion unit 90R has, in this order from the position closest to the semiconductor substrate 80, a first electrode 91R, an organic photoelectric conversion layer 92R, and a second electrode 93R. The green photoelectric conversion unit 90G has, in this order from the position closest to the red photoelectric conversion unit 90R, a first electrode 91G, an organic photoelectric conversion layer 92G, and a second electrode 93G. The blue photoelectric conversion unit 90B has, in this order from the position closest to the green photoelectric conversion unit 90G, a first electrode 91B, an organic photoelectric conversion layer 92B, and a second electrode 93B. An insulating layer 94 is further provided between the red photoelectric conversion unit 90R and the green photoelectric conversion unit 90G, and an insulating layer 95 is further provided between the green photoelectric conversion unit 90G and the blue photoelectric conversion unit 90B. The red photoelectric conversion section 90R selectively absorbs red light (e.g., wavelength of 600 nm or more and less than 700 nm), the green photoelectric conversion section 90G selectively absorbs green light (e.g., wavelength of 500 nm or more and less than 600 nm), and the blue photoelectric conversion section 90B selectively absorbs blue light (e.g., wavelength of 400 nm or more and less than 500 nm), generating electron-hole pairs.

The first electrode 91R extracts the signal charge generated in the organic photoelectric conversion layer 92R, the first electrode 91G extracts the signal charge generated in the organic photoelectric conversion layer 92G, and the first electrode 91B extracts the signal charge generated in the organic photoelectric conversion layer 92B. The first electrodes 91R, 91G, and 91B are provided, for example, for each pixel.

The first electrodes 91R, 91G, and 91B are made of, for example, a light-transmitting conductive material, specifically, ITO. The first electrodes 91R, 91G, and 91B may be made of, for example, a tin oxide-based material or a zinc oxide-based material. The tin oxide-based material is tin oxide to which a dopant has been added. The zinc oxide-based material is, for example, aluminum zinc oxide in which aluminum has been added as a dopant to zinc oxide, gallium zinc oxide in which gallium has been added as a dopant to zinc oxide, and indium zinc oxide in which indium has been added as a dopant to zinc oxide. In addition to the above, IGZO, CuI, InSbO ₄ , ZnMgO, CuInO ₂ , MgIn ₂ O ₄ , CdO, and ZnSnO ₃ can also be used. The thickness of the first electrodes 91R, 91G, and 91B is, for example, 50 nm to 500 nm.

For example, an electron transport layer may be provided between the first electrode 91R and the organic photoelectric conversion layer 92R, between the first electrode 91G and the organic photoelectric conversion layer 92G, and between the first electrode 91B and the organic photoelectric conversion layer 92B. The electron transport layer is for facilitating the supply of electrons generated in the organic photoelectric conversion layers 92R, 92G, and 92B to the first electrodes 91R, 91G, and 91B, and is made of, for example, titanium oxide or zinc oxide. The electron transport layer may be formed by laminating a titanium oxide film and a zinc oxide film. The thickness of the electron transport layer is, for example, 0.1 nm to 1000 nm, and preferably 0.5 nm to 300 nm.

The organic photoelectric conversion layers 92R, 92G, and 92B each absorb light in a selective wavelength band and convert it photoelectrically, while transmitting light in other wavelength bands. Here, the selective wavelength band light is, for example, light in a wavelength band of 600 nm or more and less than 700 nm in the organic photoelectric conversion layer 92R. For example, light in a wavelength band of 500 nm or more and less than 600 nm in the organic photoelectric conversion layer 92G. For example, light in a wavelength band of 400 nm or more and less than 500 nm in the organic photoelectric conversion layer 92B. The thickness of the organic photoelectric conversion layers 92R, 92G, and 92B is, for example, 25 nm or more and 400 nm or less, preferably 50 nm or more and 350 nm or less. More preferably, it is 150 nm or more and 300 nm or less.

The organic photoelectric conversion layers 92R, 92G, and 92B convert light energy into electrical energy, and, like the photoelectric conversion layer 24, are composed of two or more organic materials that function as p-type or n-type semiconductors. In addition to the p-type and n-type semiconductors, the organic photoelectric conversion layers 92R, 92G, and 92B further contain an organic material that photoelectrically converts light in the above-mentioned predetermined wavelength band while transmitting light in other wavelength bands, that is, a so-called dye material. Examples of such materials include, for example, phthalocyanine, indigo, and merocyanine or derivatives thereof in the organic photoelectric conversion layer 92R. Examples of materials for the organic photoelectric conversion layer 92G include subphthalocyanine, dipyrromethene, squarylium, and merocyanine or derivatives thereof. Examples of materials for the organic photoelectric conversion layer 92B include dipyrromethene derivatives represented by the above general formula (1) or general formula (2).

The organic material constituting the organic photoelectric conversion layers 92R, 92G, and 92B may be C ₆₀ fullerene or its derivative represented by the above formula (4), or C ₇₀ fullerene or its derivative represented by the above formula (5). Furthermore, as the organic material constituting the organic photoelectric conversion layers 92R, 92G, and 92B, it is preferable to use a material having hole transport properties, and specifically, thiophene derivatives, anthracene derivatives, and tetracene derivatives represented by the above formulas (6-1) to (6-17) may be used. Note that R in formulas (6-1) to (6-17) is each independently a hydrogen atom, a halogen atom, an amino group, an alkoxy group, an acylamino group, a carboxy group, an ester group, a linear alkyl group, a branched alkyl group, a cyclic alkyl group, or a substituted or unsubstituted aryl group or heteroaryl group having 4 to 30 carbon atoms. The organic photoelectric conversion layers 92R, 92G, and 92B may further contain organic materials other than those described above.

As in the above embodiment, other layers may be provided between the organic photoelectric conversion layer 92R and the second electrode 93R, between the organic photoelectric conversion layer 92G and the second electrode 93G, and between the organic photoelectric conversion layer 92B and the second electrode 93B.

The second electrode 93R is for extracting holes generated in the organic photoelectric conversion layer 92R, the second electrode 93G is for extracting holes generated in the organic photoelectric conversion layer 92G, and the second electrode 93B is for extracting holes generated in the organic photoelectric conversion layer 92G. The holes extracted from the second electrodes 93R, 93G, and 93B are discharged, for example, to a p-type semiconductor region (not shown) in the semiconductor substrate 80 via their respective transmission paths (not shown).

The second electrodes 93R, 93G, and 93B are made of conductive materials such as gold (Au), silver (Ag), copper (Cu), and aluminum (Al). As with the first electrodes 91R, 91G, and 91B, the second electrodes 93R, 93G, and 93B may be made of a transparent conductive material. In the image sensor 10C, holes taken out from the second electrodes 93R, 93G, and 93B are discharged, so that, for example, when multiple image sensors 10C are arranged in the image sensor 1 described later, the second electrodes 93R, 93G, and 93B may be provided in common to each image sensor 10C (unit pixel P). The thickness of the second electrodes 93R, 93G, and 93B is, for example, 0.5 nm or more and 100 nm or less.

The insulating layer 94 is for insulating the second electrode 93R from the first electrode 91G, and the insulating layer 95 is for insulating the second electrode 93G from the first electrode 91B. The insulating layers 94 and 95 are made of, for example, a metal oxide, a metal sulfide, or an organic material. Examples of metal oxides include silicon oxide (SiO _x ), aluminum oxide (AlO _x ), zirconium oxide (ZrO _x ), titanium oxide (TiO _x ), zinc oxide (ZnO _x ), tungsten oxide (WO _x ), magnesium oxide (MgO _x ), niobium oxide (NbO _x ), tin oxide (SnO _x ), and gallium oxide (GaO _x ). Examples of metal sulfides include zinc sulfide (ZnS) and magnesium sulfide (MgS). The band gap of the material constituting the insulating layers 94 and 95 is preferably 3.0 eV or more. The insulating layers 94 and 95 each have a thickness of, for example, 2 nm or more and 100 nm or less.

As described above, in the imaging element 10C of this modified example, for example, the organic photoelectric conversion layer 92B can be formed using a dipyrromethene derivative represented by the above general formula (1) or general formula (2), thereby obtaining the same effect as in the above embodiment.

<3. Application Examples>
(Application Example 1)
13 shows the overall configuration of an imaging device (imaging device 1) in which the imaging element 10A (or imaging elements 10B, 10C) described in the above embodiment and modified example is used for each pixel. The imaging device 1 is a CMOS image sensor, and has a pixel section 1a as an imaging area on a semiconductor substrate 30, for example, and a peripheral circuit section 130 in the peripheral region of the pixel section 1a, which is made up of a row scanning section 131, a horizontal selection section 133, a column scanning section 134, and a system control section 132, for example.

The pixel section 1a has, for example, a plurality of unit pixels P (corresponding to the image sensor 10) arranged two-dimensionally in a matrix. In the unit pixels P, for example, a pixel drive line Lread (specifically, a row selection line and a reset control line) is wired for each pixel row, and a vertical signal line Lsig is wired for each pixel column. The pixel drive line Lread transmits a drive signal for reading out signals from the pixels. One end of the pixel drive line Lread is connected to an output terminal of the row scanning section 131 corresponding to each row.

The row scanning unit 131 is a pixel driving unit that is composed of a shift register, an address decoder, etc., and drives each unit pixel P of the pixel unit 1a, for example, on a row-by-row basis. The signals output from each unit pixel P of the pixel row selected and scanned by the row scanning unit 131 are supplied to the horizontal selection unit 133 through each vertical signal line Lsig. The horizontal selection unit 133 is composed of an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

The column scanning unit 134 is composed of a shift register, an address decoder, etc., and drives each horizontal selection switch of the horizontal selection unit 133 in sequence while scanning them. By selective scanning by the column scanning unit 134, the signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to the horizontal signal line 135, and transmitted to the outside of the semiconductor substrate 30 through the horizontal signal line 135.

The circuit portion consisting of the row scanning unit 131, horizontal selection unit 133, column scanning unit 134, and horizontal signal line 135 may be formed directly on the semiconductor substrate 30, or may be disposed in an external control IC. In addition, these circuit portions may be formed on another substrate connected by a cable or the like.

The system control unit 132 receives a clock and data instructing the operation mode provided from outside the semiconductor substrate 30, and also outputs data such as internal information of the imaging device 1. The system control unit 132 further has a timing generator that generates various timing signals, and controls the driving of peripheral circuits such as the row scanning unit 131, horizontal selection unit 133, and column scanning unit 134 based on the various timing signals generated by the timing generator.

(Application Example 2)
The imaging device 1 can be applied to any type of electronic device equipped with an imaging function, such as a camera system such as a digital still camera or video camera, or a mobile phone with an imaging function. Fig. 14 shows a schematic configuration of an electronic device 2 (camera) as an example. The electronic device 2 is, for example, a video camera capable of taking still or moving images, and includes the imaging device 1, an optical system (optical lens) 310, a shutter device 311, a drive unit 313 for driving the imaging device 1 and the shutter device 311, and a signal processing unit 312.

The optical system 310 guides image light (incident light) from a subject to the pixel section 1a of the imaging device 1. This optical system 310 may be composed of multiple optical lenses. The shutter device 311 controls the light irradiation period and light blocking period to the imaging device 1. The drive section 313 controls the transfer operation of the imaging device 1 and the shutter operation of the shutter device 311. The signal processing section 312 performs various signal processing on the signal output from the imaging device 1. The video signal Dout after signal processing is stored in a storage medium such as a memory, or is output to a monitor, etc.

Furthermore, the imaging device 1 can also be applied to the following electronic devices (capsule endoscope 10100 and moving objects such as vehicles).

＜4. Application Examples＞
(Application example to an in-body information acquisition system)
Furthermore, the technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

Figure 15 is a block diagram showing an example of the general configuration of a patient's internal body information acquisition system using a capsule endoscope to which the technology disclosed herein (the present technology) can be applied.

The internal body information acquisition system 10001 comprises a capsule endoscope 10100 and an external control device 10200.

The capsule endoscope 10100 is swallowed by the patient during the examination. The capsule endoscope 10100 has an imaging function and a wireless communication function, and while moving inside the organs such as the stomach and intestines by peristalsis or the like until it is naturally expelled from the patient, it sequentially captures images of the inside of the organ (hereinafter also referred to as in-vivo images) at predetermined intervals, and sequentially wirelessly transmits information about the in-vivo images to an external control device 10200 outside the body.

The external control device 10200 comprehensively controls the operation of the in-vivo information acquisition system 10001. The external control device 10200 also receives information about the in-vivo image transmitted from the capsule endoscope 10100, and generates image data for displaying the in-vivo image on a display device (not shown) based on the received information about the in-vivo image.

In this manner, the intrabody information acquisition system 10001 can obtain intrabody images capturing the state of the patient's body at any time from the time the capsule endoscope 10100 is swallowed to the time it is expelled.

The configuration and functions of the capsule endoscope 10100 and the external control device 10200 are described in more detail.

The capsule endoscope 10100 has a capsule-shaped housing 10101, which houses a light source unit 10111, an imaging unit 10112, an image processing unit 10113, a wireless communication unit 10114, a power supply unit 10115, a power supply unit 10116, and a control unit 10117.

The light source unit 10111 is composed of a light source such as an LED (light emitting diode) and irradiates light onto the imaging field of view of the imaging unit 10112.

The imaging unit 10112 is composed of an imaging element and an optical system consisting of multiple lenses provided in front of the imaging element. Reflected light of light irradiated onto the body tissue to be observed (hereinafter referred to as observation light) is collected by the optical system and enters the imaging element. In the imaging unit 10112, the imaging element photoelectrically converts the observation light incident thereon, and an image signal corresponding to the observation light is generated. The image signal generated by the imaging unit 10112 is provided to the image processing unit 10113.

The image processing unit 10113 is configured with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and performs various signal processing on the image signal generated by the imaging unit 10112. The image processing unit 10113 provides the image signal that has been subjected to the signal processing to the wireless communication unit 10114 as RAW data.

The wireless communication unit 10114 performs predetermined processing such as modulation processing on the image signal that has been subjected to signal processing by the image processing unit 10113, and transmits the image signal to the external control device 10200 via the antenna 10114A. The wireless communication unit 10114 also receives a control signal related to the drive control of the capsule endoscope 10100 from the external control device 10200 via the antenna 10114A. The wireless communication unit 10114 provides the control signal received from the external control device 10200 to the control unit 10117.

The power supply unit 10115 is composed of an antenna coil for receiving power, a power regeneration circuit that regenerates power from the current generated in the antenna coil, and a boost circuit, etc. In the power supply unit 10115, power is generated using the principle of so-called non-contact charging.

The power supply unit 10116 is composed of a secondary battery and stores the power generated by the power supply unit 10115. In FIG. 15, to avoid cluttering the drawing, arrows and other symbols indicating the destination of the power supply from the power supply unit 10116 are omitted, but the power stored in the power supply unit 10116 is supplied to the light source unit 10111, the imaging unit 10112, the image processing unit 10113, the wireless communication unit 10114, and the control unit 10117 and can be used to drive these units.

The control unit 10117 is composed of a processor such as a CPU, and appropriately controls the operation of the light source unit 10111, the imaging unit 10112, the image processing unit 10113, the wireless communication unit 10114, and the power supply unit 10115 in accordance with control signals transmitted from the external control device 10200.

The external control device 10200 is composed of a processor such as a CPU or a GPU, or a microcomputer or a control board in which a processor and a storage element such as a memory are mixed. The external control device 10200 controls the operation of the capsule endoscope 10100 by transmitting a control signal to the control unit 10117 of the capsule endoscope 10100 via the antenna 10200A. In the capsule endoscope 10100, for example, the light irradiation conditions for the observation object in the light source unit 10111 may be changed by the control signal from the external control device 10200. In addition, the imaging conditions (for example, the frame rate and exposure value in the imaging unit 10112) may be changed by the control signal from the external control device 10200. In addition, the contents of the processing in the image processing unit 10113 and the conditions for the wireless communication unit 10114 to transmit an image signal (for example, the transmission interval, the number of transmitted images, etc.) may be changed by the control signal from the external control device 10200.

The external control device 10200 also applies various image processing to the image signal transmitted from the capsule endoscope 10100 to generate image data for displaying the captured in-vivo image on the display device. The image processing can include various signal processing such as development processing (demosaic processing), high image quality processing (band enhancement processing, super-resolution processing, NR (Noise reduction) processing, and/or image stabilization processing, etc.), and/or enlargement processing (electronic zoom processing). The external control device 10200 controls the driving of the display device to display the captured in-vivo image based on the generated image data. Alternatively, the external control device 10200 may record the generated image data in a recording device (not shown) or print it out on a printing device (not shown).

An example of an in-vivo information acquisition system to which the technology disclosed herein can be applied has been described above. The technology disclosed herein can be applied to, for example, the imaging unit 10112 of the configurations described above. This improves detection accuracy.

(Application example to endoscopic surgery system)
The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

Figure 16 is a diagram showing an example of the general configuration of an endoscopic surgery system to which the technology disclosed herein (the present technology) can be applied.

Figure 16 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

The endoscope 11100 is composed of a lens barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 at a predetermined length, and a camera head 11102 connected to the base end of the lens barrel 11101. In the illustrated example, the endoscope 11100 is configured as a so-called rigid lens barrel having a rigid lens barrel 11101, but the endoscope 11100 may be configured as a so-called flexible lens barrel having a flexible lens barrel.

An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed in the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from the object to be observed is focused onto the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to the camera control unit (CCU) 11201 as RAW data.

The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and controls the overall operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102, and performs various image processing on the image signal, such as development processing (demosaic processing), in order to display an image based on the image signal.

The display device 11202, under the control of the CCU 11201, displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

The light source device 11203 is composed of a light source such as an LED (light emitting diode) and supplies illumination light to the endoscope 11100 when photographing the surgical site, etc.

The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

The treatment tool control device 11205 controls the operation of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity in order to ensure a clear field of view for the endoscope 11100 and to ensure a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to surgery. The printer 11208 is a device capable of printing various types of information related to surgery in various formats such as text, images, or graphs.

The light source device 11203 that supplies irradiation light to the endoscope 11100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation object with laser light from each of the RGB laser light sources in a time-division manner and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The driving of the image sensor of the camera head 11102 may be controlled in synchronization with the timing of the change in the light intensity to acquire images in a time-division manner, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

The light source device 11203 may also be configured to supply light of a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band of light is irradiated compared to the irradiation light (i.e., white light) during normal observation, a predetermined tissue such as blood vessels on the mucosal surface is photographed with high contrast, so-called narrow band imaging. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained by fluorescence generated by irradiating excitation light. In fluorescence observation, excitation light is irradiated to the body tissue and the fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and excitation light corresponding to the fluorescence wavelength of the reagent is irradiated to the body tissue to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and/or excitation light corresponding to such special light observation.

Figure 17 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 16.

The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other by a transmission cable 11400 so that they can communicate with each other.

The lens unit 11401 is an optical system provided at the connection with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

The imaging element constituting the imaging unit 11402 may be one (so-called single-plate type) or multiple (so-called multi-plate type). When the imaging unit 11402 is configured as a multi-plate type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining them. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. In addition, when the imaging unit 11402 is configured as a multi-plate type, multiple lens units 11401 may be provided corresponding to each imaging element.

Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the telescope tube 11101, immediately after the objective lens.

The driving unit 11403 is composed of an actuator, and moves the zoom lens and focus lens of the lens unit 11401 a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be appropriately adjusted.

The communication unit 11404 is configured by a communication device for transmitting and receiving various information between the communication unit 11404 and the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

In addition, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201, and supplies it to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of capturing the image, and/or information specifying the magnification and focus of the captured image.

The above-mentioned frame rate, exposure value, magnification, focus, and other imaging conditions may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

The camera head control unit 11405 controls the operation of the camera head 11102 based on a control signal from the CCU 11201 received via the communication unit 11404.

The communication unit 11411 is configured by a communication device for transmitting and receiving various information between the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

In addition, the communication unit 11411 transmits a control signal to the camera head 11102 for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, etc.

The image processing unit 11412 performs various image processing on the image signal, which is RAW data transmitted from the camera head 11102.

The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100, and the display of the captured images obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

The control unit 11413 also displays the captured image showing the surgical site on the display device 11202 based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, and the like, by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 displays the captured image on the display device 11202, it may use the recognition result to superimpose various types of surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable corresponding to communication of electrical signals, an optical fiber corresponding to optical communication, or a composite cable of these.

In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

An example of an endoscopic surgery system to which the technology disclosed herein can be applied has been described above. The technology disclosed herein can be applied to the imaging unit 11402 of the configuration described above. By applying the technology disclosed herein to the imaging unit 11402, detection accuracy is improved.

Although an endoscopic surgery system has been described here as an example, the technology disclosed herein may also be applied to other systems, such as microsurgical systems.

(Example of application to moving objects)
The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, a construction machine, or an agricultural machine (tractor).

Figure 18 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology disclosed herein can be applied.

The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 18, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside vehicle information detection unit 12030, an inside vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional configurations of the integrated control unit 12050 are a microcomputer 12051, an audio/video output unit 12052, and an in-vehicle network I/F (interface) 12053.

The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

The body system control unit 12020 controls the operation of various devices installed in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, tail lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals from various switches transmitted from a portable device that replaces a key can be input to the body system control unit 12020. The body system control unit 12020 accepts the input of these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the image capturing unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the image capturing unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, or characters on the road surface based on the received images.

The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

The microcomputer 12051 can calculate the control target values of the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an Advanced Driver Assistance System (ADAS), including avoiding or mitigating a vehicle collision, following a vehicle based on the distance between vehicles, maintaining vehicle speed, warning a vehicle collision, or warning a vehicle from leaving a lane.

In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside-vehicle information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

The audio/image output unit 12052 transmits at least one output signal of audio and image to an output device capable of visually or audibly notifying the occupants of the vehicle or the outside of the vehicle of information. In the example of Fig. 18, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

Figure 19 is a diagram showing an example of the installation position of the imaging unit 12031.

In Figure 19, the imaging unit 12031 has imaging units 12101, 12102, 12103, 12104, and 12105.

The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at the front nose, side mirrors, rear bumper, back door, and upper part of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin is mainly used to detect a preceding vehicle, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

19 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, the microcomputer 12051 can extract, as a preceding vehicle, the three-dimensional object that is the closest to the vehicle 12100 on the path of travel and travels in approximately the same direction as the vehicle 12100 at a predetermined speed (for example, 0 km/h or more) by calculating the distance to each three-dimensional object within the imaging range 12111 to 12114 and the change in this distance over time (relative speed to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set the vehicle distance to be secured in advance in front of the preceding vehicle and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on the driver's operation.

For example, the microcomputer 12051 classifies and extracts three-dimensional object data on three-dimensional objects, such as two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, based on the distance information obtained from the imaging units 12101 to 12104, and can use the data to automatically avoid obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines the collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or exceeds a set value and there is a possibility of a collision, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio/image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio/image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

5. Examples
Next, examples of the present disclosure will be described in detail. In Experiment 1, a dipyrromethene derivative represented by the above general formula (1) or general formula (2) was used to fabricate a photoelectric conversion element having a cross-sectional configuration shown in Fig. 20 as a device sample, and the device characteristics were evaluated. In Experiment 2, a simulation was performed on the substituent dependency of the absorption wavelength of the dipyrromethene derivative represented by general formula (1).

[Experiment 1]
(Experimental Example 1)
A sputtering device was used to form an ITO film having a thickness of 100 nm on a silicon substrate 1011. This ITO film was patterned by photolithography and etching to form an ITO lower electrode 1012. Next, the silicon substrate 1011 with the ITO lower electrode 1012 was cleaned by UV/ozone treatment, and then the silicon substrate 1011 was transferred to a vacuum deposition machine, and an organic material film was formed on the silicon substrate 1011 by using a resistance heating method while rotating the substrate holder under a reduced pressure of 1×10 ⁻⁵ Pa or less. First, an electron blocking material shown in the following formula (9) was formed into a film having a thickness of 10 nm at a substrate temperature of 0° C. to form an electron blocking layer 1013. Next, a dipyrromethene derivative shown in the following formula (1-1), BP-rBDT shown in the following formula (8), and C ₆₀ fullerene (above formula (4)) were deposited at deposition rates of 0.50 Å/sec, 0.50 Å/sec, and 0.25 Å/sec, respectively, at a substrate temperature of 40° C., so that the mixed layer had a thickness of 230 nm, to form a photoelectric conversion layer 1014. Next, a hole blocking material shown in the following formula (7) was deposited at a substrate temperature of 0° C. to a thickness of 10 nm, to form a hole blocking layer 1015. Finally, the silicon substrate 1011 was transferred to a sputtering device, and ITO was deposited on the hole blocking layer 1015 to a thickness of 50 nm, to form an ITO upper electrode 1016. By the above-mentioned fabrication method, a photoelectric conversion element (Experimental Example 1) having a photoelectric conversion area of 1 mm×1 mm was fabricated.

(Experimental Example 2)
A photoelectric conversion element (Experimental Example 2) was produced in the same manner as in Experimental Example 1, except that the dipyrromethene derivative shown in the following formula (10) was used instead of the dipyrromethene derivative shown in the formula (1-1) used in Experimental Example 1.

(Experimental Example 3)
A photoelectric conversion element (Experimental Example 3) was prepared in the same manner as in Experimental Example 1, except that the dipyrromethene derivative shown in the following formula (11) was used instead of the dipyrromethene derivative shown in the formula (1-1) used in Experimental Example 1.

(Experimental Example 4)
A photoelectric conversion element (Experimental Example 4) was produced in the same manner as in Experimental Example 1, except that a subphthalocyanine derivative represented by the following formula (12) was used instead of the dipyrromethene derivative represented by the formula (1-1) used in Experimental Example 1.

For the photoelectric conversion elements produced in Experimental Examples 1 to 4, the absorptance at wavelengths of 450 nm and 560 nm was measured, and the device characteristics (dark current characteristics, external quantum efficiency (EQE), and response time) were evaluated using the following method. Table 1 summarizes the evaluation results of the absorptance at each wavelength and the device characteristics, along with the compounds used in the photoelectric conversion layer in each experimental example. In Table 1, the device characteristics of Experimental Example 1 are standardized to 1.00, and the device characteristics of Experimental Examples 2 to 4 are expressed as relative values.

(Evaluation of Dark Current and External Quantum Efficiency (EQE))
The wavelength of light irradiated from a blue LED light source through a bandpass filter to the photoelectric conversion element was set to 450 nm, the amount of light was set to 1.62 μW/ ^cm2 , the bias voltage applied between the electrodes of the photoelectric conversion element was controlled using a semiconductor parameter analyzer, and the voltage applied to the lower electrode relative to the upper electrode was swept to obtain a current-voltage curve. The dark current value and the bright current value in the reverse bias applied state (voltage applied state of -2.6 V) were obtained, the dark current value was subtracted from the bright current value, and the EQE was calculated from the value.

(Response Time Evaluation)
The wavelength of light irradiated from a blue LED light source to the photoelectric conversion element through a bandpass filter was set to 450 nm, the light amount was set to 1.62 μW/ ^cm2 , the voltage applied to the LED driver was controlled by a function generator, and pulsed light was irradiated from the upper electrode side of the photoelectric conversion element. The bias voltage applied between the electrodes of the photoelectric conversion element was set to a voltage of -2.6 V applied to the lower electrode relative to the upper electrode, and the pulsed light was irradiated, and the attenuation waveform of the current was observed using an oscilloscope. Immediately after the light pulse irradiation, the time it took for the current to attenuate to 3% from the current at the time of the light pulse irradiation was measured, and this was taken as the response time, which is an index of the response speed.

Experimental Example 1, which used the dipyrromethene derivative represented by formula (1-1), had an absorptance of 74% for 450 nm blue light and 6.4% for 560 nm green light. This shows that the photoelectric conversion element produced in Experimental Example 1 selectively absorbs light in the blue wavelength range.

Experimental Examples 2 and 3, which used the dipyrromethene derivatives represented by formulas (10) and (11), respectively had absorptivities of 48% and 28% for 450 nm light and 29% and 39% for 560 nm light, and were found to have higher light absorptivities for green light than Experimental Example 1. Experimental Example 4, which used the subphthalocyanine derivative shown in formula (12), had absorptivities of 18% for 450 nm light and 90% for 560 nm light, and was found to selectively absorb green light compared to Experimental Examples 1 to 3.

In terms of device characteristics, it was found that Experimental Example 1 had superior dark current characteristics, EQE, and response time compared to Experimental Examples 2 and 3. It was also found that Experimental Example 1 had superior EQE compared to Experimental Example 4.

From the above, it was found that the photoelectric conversion element of Experimental Example 1 has selective absorption in the blue band and a high light absorption coefficient, and that excitons generated by light absorption quickly dissociate into electrons and holes, which are transported to the corresponding electrodes without recombining.

[Experiment 2]
Table 2 shows a simulation of the change in absorption wavelength when various substituents are introduced into the meso position (X) of the dipyrromethene derivative shown in the above general formula (1), in which Y1 to Y3 and Y4 to Y6 each have a hydrogen (H) atom, a fluorine (F) or a methyl (Me) group, Y7 and Y8 have a fluorine (F) atom, and Z has a boron (B) atom. Note that the values in Table 2 are values in an isolated vacuum state without considering the solvent. In a solvent or an organic layer, the absorption wavelength is lengthened by about 50 nm to 100 nm.

From Table 2, it was found that the absorption wavelength of the dipyrromethene derivative represented by the general formula (1) tends to be shortened by introducing an electron-donating substituent such as an amino group (NH ₂ ), a dimethylamino group (NMe ₂ ), a hydroxyl group (OH), or a methoxy group (OMe) into the meso position (X). This tendency is presumed to be the same for the dipyrromethene derivative represented by the general formula (2) having a similar molecular skeleton. Therefore, it is considered that a photoelectric conversion element having high absorption efficiency for light in the blue band and excellent external quantum efficiency can be realized by using the dipyrromethene derivative represented by the general formula (1) or (2) as the dye material constituting the photoelectric conversion layer.

Although the above describes the embodiments, modifications, and examples, the present disclosure is not limited to the above embodiments, and various modifications are possible. For example, the number and ratio of the organic photoelectric conversion units and the inorganic photoelectric conversion units are not limited, and an imaging element may be configured to have one organic photoelectric conversion unit and two inorganic photoelectric conversion units. In that case, for example, the organic photoelectric conversion unit selectively detects wavelengths in the blue band (blue light) and performs photoelectric conversion, and the two inorganic photoelectric conversion units are embedded and formed in a semiconductor substrate, and a green inorganic photoelectric conversion unit that selectively detects wavelengths in the green band (green light) and performs photoelectric conversion, and a red inorganic photoelectric conversion unit that selectively detects wavelengths in the red band (red light) and performs photoelectric conversion are stacked in the thickness direction.

Furthermore, in the above embodiments, an example has been shown in which the multiple electrodes constituting the lower electrode 21 are composed of two electrodes, a readout electrode 21A and a storage electrode 21B, but in addition to this, three or four or more electrodes such as a transfer electrode or an exhaust electrode may be provided.

Note that the effects described in this specification are merely examples and are not limiting, and other effects may also exist.

［２］
前記有機層は、青色帯域の波長を検出する、前記［１］に記載の撮像素子。
［３］
前記有機層は光電変換層を有し、
前記光電変換層は、前記式（１－１）～式（１－２４）および式（２－１）～式（２－６）で表されるジピロメテン誘導体を少なくとも１種含む、前記［１］乃至［２］のうちのいずれか１つに記載の撮像素子。
［４］
前記光電変換層は、波長４５０ｎｍの吸収率が７０％以上、且つ、５６０ｎｍ以上７００ｎｍ以下の波長の吸収率が２０％未満である、前記［３］に記載の撮像素子。
［５］
前記光電変換層は、さらに２種類以上の有機半導体材料を含んで構成されている、前記［３］または［４］に記載の撮像素子。
［６］
前記光電変換層は、さらにフラーレンまたはその誘導体と、正孔輸送性材料とを含んで構成されている、前記［３］乃至［５］のうちのいずれか１つに記載の撮像素子。
［７］
前記有機層は複数の層からなり、
前記複数の層のうちの少なくとも１層が、前記式（１－１）～式（１－２４）および式（２－１）～式（２－６）で表されるジピロメテン誘導体を少なくとも１種含む、前記［１］乃至［６］のうちのいずれか１つに記載の撮像素子。
［８］
前記第１電極は複数の電極からなる、前記［１］乃至［７］のうちのいずれか１つに記載の撮像素子。
［９］
前記第１電極と前記光電変換層との間に、さらに第１の電荷ブロック層が設けられている、前記［３］乃至［８］のうちのいずれか１つに記載の撮像素子。
［１０］
前記光電変換層と前記第２電極との間に、さらに、第２の電荷ブロック層が設けられている、前記［３］乃至［９］のうちのいずれか１つに記載の撮像素子。
［１１］
１または複数の有機光電変換部がそれぞれ設けられている複数の画素を備え、
前記有機光電変換部は、
第１電極と、
前記第１電極と対向配置された第２電極と、
前記第１電極と前記第２電極との間に設けられると共に、下記式（１－１）～式（１－２４）および式（２－１）～式（２－６）で表されるジピロメテン誘導体を少なくとも１種含む有機層と
を有する撮像装置。

［１２］
各画素には、１または複数の前記有機光電変換部と、前記有機光電変換部とは異なる波長域の光電変換を行う１または複数の無機光電変換部とが積層されている、前記［１１］に記載の撮像装置。
［１３］
前記式（１－１）～式（１－２４）および式（２－１）～式（２－６）で表されるジピロメテン誘導体を少なくとも１種含む前記有機層を有する前記有機光電変換部は、入射光に対して、他の前記有機光電変換部および前記無機光電変換部よりも近い位置に配設されている、前記［１２］に記載の撮像装置。
［１４］
前記無機光電変換部は、半導体基板に埋め込み形成され、
前記有機光電変換部は、前記半導体基板の第１の面側に形成されている、前記［１２］または［１３］に記載の撮像装置。
［１５］
前記半導体基板は前記第１の面と対向する第２の面を有し、前記第２の面側に多層配線層が形成されている、前記［１４］に記載の撮像装置。
［１６］
前記有機光電変換部は青色光の光電変換を行い、
前記半導体基板内に、緑色光の光電変換を行う前記無機光電変換部と、赤色光の光電変換を行う前記無機光電変換部とが積層されている、前記［１４］または［１５］に記載の撮像装置。
［１７］
各画素では、互いに異なる波長域の光電変換を行う複数の前記有機光電変換部が積層されている、前記［１１］乃至［１６］のうちのいずれか１つに記載の撮像装置。 The present disclosure may have the following configuration: According to the present technology having the following configuration, an organic layer is formed using at least one of the dipyrromethene derivatives represented by formulas (1-1) to (1-24) and formulas (2-1) to (2-6) , and therefore the absorption efficiency of light with a predetermined wavelength (specifically, blue light) is improved, and the external quantum efficiency can be improved.
[1]
A first electrode;
a second electrode disposed opposite the first electrode;
an organic layer provided between the first electrode and the second electrode, the organic layer including at least one dipyrromethene derivative represented by any one of the following formulas (1-1) to (1-24) and (2-1) to (2-6) :

[2]
The imaging element according to any one of claims 1 to 4, wherein the organic layer detects wavelengths in a blue band.
[3]
The organic layer has a photoelectric conversion layer,
The image sensor according to any one of [1] to [2], wherein the photoelectric conversion layer contains at least one dipyrromethene derivative represented by the formulas (1-1) to (1-24) and the formulas (2-1) to (2-6) .
[4]
The image sensor according to [3], wherein the photoelectric conversion layer has an absorptance of 70% or more at a wavelength of 450 nm and an absorptance of less than 20% at a wavelength of 560 nm or more and 700 nm or less.
[5]
The imaging element according to [3] or [4], wherein the photoelectric conversion layer further contains two or more types of organic semiconductor materials.
[6]
The imaging element according to any one of [3] to [5], wherein the photoelectric conversion layer further contains a fullerene or a derivative thereof, and a hole transporting material.
[7]
The organic layer is composed of a plurality of layers,
The imaging element according to any one of the above [1] to [6] , wherein at least one layer of the plurality of layers contains at least one kind of dipyrromethene derivative represented by the above formulas (1-1) to (1-24) and (2-1) to (2-6) .
[8]
The imaging element according to any one of [1] to [7] , wherein the first electrode is made up of a plurality of electrodes.
[9]
The imaging element according to any one of [3] to [8] , further comprising a first charge blocking layer between the first electrode and the photoelectric conversion layer.
[10]
The imaging element according to any one of [3] to [9] , further comprising a second charge blocking layer between the photoelectric conversion layer and the second electrode.
[11]
A plurality of pixels each having one or a plurality of organic photoelectric conversion units provided therein;
The organic photoelectric conversion unit is
A first electrode;
a second electrode disposed opposite the first electrode;
and an organic layer provided between the first electrode and the second electrode, the organic layer including at least one dipyrromethene derivative represented by the following formulas (1-1) to (1-24) and (2-1) to (2-6) .

[12]
The imaging device according to [11], wherein each pixel includes one or more of the organic photoelectric conversion units and one or more inorganic photoelectric conversion units that perform photoelectric conversion in a wavelength range different from that of the organic photoelectric conversion units.
[13]
The organic photoelectric conversion unit having the organic layer containing at least one kind of dipyrromethene derivative represented by the formulas (1-1) to (1-24) and the formulas (2-1) to (2-6) is disposed at a position closer to incident light than the other organic photoelectric conversion units and the inorganic photoelectric conversion unit.
[14]
The inorganic photoelectric conversion unit is formed by embedding the inorganic photoelectric conversion unit in a semiconductor substrate,
The imaging device according to [12] or [13] , wherein the organic photoelectric conversion section is formed on a first surface side of the semiconductor substrate.
[15]
The imaging device according to [14] , wherein the semiconductor substrate has a second surface opposite to the first surface, and a multilayer wiring layer is formed on the second surface side.
[16]
the organic photoelectric conversion unit performs photoelectric conversion of blue light,
The imaging device according to [14] or [15] , wherein the inorganic photoelectric conversion unit that performs photoelectric conversion of green light and the inorganic photoelectric conversion unit that performs photoelectric conversion of red light are stacked within the semiconductor substrate.
[17]
The imaging device according to any one of [11] to [16] , wherein in each pixel, a plurality of the organic photoelectric conversion units that perform photoelectric conversion in mutually different wavelength ranges are stacked.

This application claims priority based on Japanese Patent Application No. 2019-147802, filed on August 9, 2019 in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

Those skilled in the art will appreciate that various modifications, combinations, subcombinations, and variations may occur to those skilled in the art depending on design requirements and other factors, and that these are intended to be within the scope of the appended claims and their equivalents.

Claims (17)

A first electrode;
a second electrode disposed opposite the first electrode;
an organic layer provided between the first electrode and the second electrode, the organic layer including at least one dipyrromethene derivative represented by any one of the following formulas (1-1) to (1-24) and (2-1) to (2-6) :

The image sensor according to claim 1, wherein the organic layer detects wavelengths in the blue band. The organic layer has a photoelectric conversion layer,
2. The image sensor according to claim 1, wherein the photoelectric conversion layer contains at least one dipyrromethene derivative represented by any one of formulas (1-1) to (1-24) and formulas (2-1) to (2-6) . The image sensor according to claim 3, wherein the photoelectric conversion layer has an absorption rate of 70% or more at a wavelength of 450 nm and an absorption rate of less than 20% at wavelengths of 560 nm or more and 700 nm or less. The image sensor according to claim 3, wherein the photoelectric conversion layer further comprises two or more types of organic semiconductor materials. The image sensor according to claim 3, wherein the photoelectric conversion layer further comprises fullerene or a derivative thereof and a hole transport material. The organic layer is composed of a plurality of layers,
2. The image sensor according to claim 1, wherein at least one of the plurality of layers contains at least one kind of dipyrromethene derivative represented by any one of formulas (1-1) to (1-24) and formulas (2-1) to (2-6) . The imaging element according to claim 1, wherein the first electrode is made up of a plurality of electrodes. The imaging element according to claim 3, further comprising a first charge blocking layer between the first electrode and the photoelectric conversion layer. The imaging element according to claim 3, further comprising a second charge blocking layer between the photoelectric conversion layer and the second electrode. A plurality of pixels each having one or a plurality of organic photoelectric conversion units provided therein;
The organic photoelectric conversion unit is
A first electrode;
a second electrode disposed opposite the first electrode;
and an organic layer provided between the first electrode and the second electrode, the organic layer including at least one dipyrromethene derivative represented by the following formulas (1-1) to (1-24) and (2-1) to (2-6) .

The imaging device according to claim 11 , wherein each pixel includes one or more of the organic photoelectric conversion units and one or more inorganic photoelectric conversion units that perform photoelectric conversion in a wavelength range different from that of the organic photoelectric conversion units. The imaging device according to claim 12, wherein the organic photoelectric conversion unit having the organic layer containing at least one of the dipyrromethene derivatives represented by the formulas (1-1) to (1-24) and the formulas (2-1) to (2-6) is disposed at a position closer to incident light than the other organic photoelectric conversion units and the inorganic photoelectric conversion unit. The inorganic photoelectric conversion unit is formed by embedding the inorganic photoelectric conversion unit in a semiconductor substrate,
The imaging device according to claim 12 , wherein the organic photoelectric conversion section is formed on a first surface side of the semiconductor substrate. The imaging device according to claim 14 , wherein the semiconductor substrate has a second surface opposite to the first surface, and a multilayer wiring layer is formed on the second surface side. the organic photoelectric conversion unit performs photoelectric conversion of blue light,
The imaging device according to claim 14 , wherein the inorganic photoelectric conversion section that performs photoelectric conversion of green light and the inorganic photoelectric conversion section that performs photoelectric conversion of red light are stacked in the semiconductor substrate. The imaging device according to claim 11 , wherein each pixel includes a plurality of the organic photoelectric conversion units that perform photoelectric conversion in mutually different wavelength ranges.

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